CABLE CONTROLLED TOGGLE BOLT HAND

OK, all, here's another way to make a cable controlled hand.  This method uses common items that can be bought at a hardware store.  I apologize for the "rushed" look to it, but it was done in an hour or so.  I didn't build the entire hand yet, just enough to get the idea across.  In time I may put up the finished hand, and perhaps even a skin.  I think it'll give you the idea, but if not feel free to drop me a line.

Materials:

• 14 toggle bolts, you may want to use different size as you go down the fingers, but I choose not too

• 15-20 screws (with nuts)

• material for the "palm" plywood can be used as can metal

• 1 small hinge

• (optional) a second hinge, larger then the first

• cables (bike cables will work)

• cable stops

Tools required:

• screwdriver

• file (or dremel with sanding drum or grinding stone)

• drill with bit same size or slightly larger then the screws

• pliers

OK here we go.  

A toggle bolt, the basis for the fingers.  They come in different sizes, so choose the one best for your hand.  I used what I had laying around.  

The areas in "circles" will give you trouble if you don't take care of them.  They must be sanded down or the bolt will remain at an angle.  I used a dremel with a sanding drum to do that.  The simple technique is to fold the bolt in half and carefully sand the corners (and sometimes part of the top) away.

I removed one half for illustration purposes, you don't have to do that, but if you feel up to it you can, but be careful.

After sanding, you can see that the sharp corners have been removed, as well as part of the top surface.  This eliminated the problem of the toggle bolts not laying flat.

At this point (if you have taken the bolt apart) you may want to add a second spring to allow the bolt to return to it's open position.  The single spring that is installed in the toggle bolts doesn't seem to have enough "umph" to do this when a cable is attached.   In the picture below you can see one of the "standard" springs if you look closely in the center of bolt 2.  I would advise adding the second spring opposite the pre-installed spring if you choose to do so.  

If you took the bolt apart, reassemble it now, so we can begin constructing the fingers.

To begin building the fingers, you need to drill holes to bolt them together.  Drill a hole in each end of each bolt as in the picture above.  Make sure that they line up when the bolts are assembled so that they can be easily bolted together.  Do so as in the picture above.  Repeat this for all the fingers, and remember the thumb is made of only 2 toggle bolts!

This top view of the same finger allows you to see the areas that have been sanded away.  Now that you have the fingers built you can begin to think about the palm.  In the oversimplified picture below you can see the general layout of the hand, as well as the way to build the thumb's third movement (toward the palm)

The smaller of the two hinges is used for the thumb.  It must be cut to allow the toggle bolt to fit over it.  The sketch is a general guide for cutting the hinge, depending on your size bolts it may need adjusted.  The hinge for the wrist is the larger, and isn't required, but if you want to have the wrist move, you'll probably want it.  The palm can be made of plywood, or metal.  

Well, that the basic idea.  Feel free to contact me if you need any additional info and/or help